XC42 Analog Input Pin#8 Internal Short?

Arbutus 3 years ago in Expansion modules / XC4x updated by Gustav Widén (System support) 3 years ago 1

We had a XC42 where we use a hall effect analog device that was mapped to pin 8 and configured as an analog input. The device was connected to Vref A so uses a supply voltage of +5v and provides 0.5-4.5v thru 180 deg of rotation. We first started to see it only indicating from 2.5-4.5v and then eventually we got fixed values that fluctuated based on if the hall effect magnet was present or not. After some trouble shooting we removed the wire from pin at a connector and were getting a fixed voltage of around 4v at pin 8. With this removed the magnet rotated gave us 0.5-4.5v at the output of the sensor.

A data sheet of the sensor is attached. Model # is RTP180LVNAA

We ended up remapping the input to pin 52 and it all worked fine again.

It almost seems like the pull up resistor in the channel was "turned on"???Honeywell RTP Sensor

I must say I find it hard to believe that a problem with this symptom could be damage to the VIN. 

One possible explanation for the symptoms you describe could be if the wire that was disconnected was the sensor ground

With sensor loss of ground, it is possible to get some strange in-range failures. 

But if you still suspect the module is damaged, please contact your local sales representative to discuss return for investigation/repair.